I think I found the problem. You're not using Dell's native white point and relying on Colormunki to set target white point through video card vcgt RGB LUT curve adjusts (see screengrab showing vcgt green channel which is the same as the red, but blue curve is really wonky).

I'll have to correct myself on my previous post and say I did have similar step wedge issues choosing target white point with Colormunki Display profiles on both my previous fluorescent backlit Dell and LG LED.

If you need to achieve a neutral white point on your Dell, I'ld suggest you adjust visually through the display's OSD RGB gains just as I had to do. The Colormunki may not see this as exact D65/6500K as written into the icc display profile but it won't affect overall memory colors that much except maybe slight luminance shifts in reds and blues in color managed previews. I haven't tested this because it's impossible to do so without a measuring device. My prints still match my monitor.

You can see what the Colormunki wrote in white point XY numbers loading the display profile as RGB Working Space in Photoshop's CustomRGB dialog box in Color Settings and plotting those numbers on a Plankian Locus diagram which should place the coordinates close to the area regarded as 6500K.

My LG's XY numbers according to Colormunki says my white is slightly magenta-ish blue but it doesn't seem to affect color managed previews . Visually my white point has never looked more neutral. If I adjust RGB gains to get Colormunki Display to give me 6500K XY numbers read in Photoshop Color Settings CustomRGB, my display looks too green. But this red/green white point tint color war has been going on with Xrite products with my iMac, Dell and LG displays for years that I've been told drift from expected standard sRGB gamut and thus makes the colormeter see something different.

As I said before I still get screen to print matches on edited and finished Raw images.

Also make sure you're making a version 2 (not version 4) display profile.

Wouldn't cataracts influence the perception on both print and screen as well ?

I don't know. I'm not an optometrist and I don't know what the effects of cataracts do to color perception. I was under the impression it made things look foggy or like tunnel vision.

It might be a separate LUT loader issue that's screwing up the step wedge since the OP is on a Windows system. Macs have their vcgt RGB video card correction curves built into the icc profile and load on startup as one file.

Thank you for telling me about the ColorMunki's preferences settings. I completely forgot about them when I recently upgraded to the latest ColorMunki Photo software v1.2.4. After reading your reply, I changed the ColorMunki preferences (to as seen below) and made a second icc profile (attached). Unfortunately, I still get rainbow step wedges.

1. You said "You're not using Dell's native white point and relying on Colormunki to set target white point."

But isn't this the way it's suppose to work? Isn't the ColorMunki suppose to take control of my monitor and set its white point? Are you saying there is something wrong with the Dell 3007 that makes it unresponsive to the ColorMunki's command to set the targeted white point?

2. You said "If you need to achieve a neutral white point on your Dell, I'ld suggest you adjust visually through the display's OSD RGB gains just as I had to do"

The Dell 3007 came with optional OSD software, but I never installed it because I wanted the ColorMunki and GPU duo to control my monitor. (If I remember correctly, the Dell OSD software interfered with the ColorMunki software, but that was 10 yrs ago.) Right now I only have two control buttons on the Dell 3007: one for brightness control and the other to power on/off. Should I install this OSD software here and manually adjust the whiteness of the display to match what my eye thinks neutral white looks like? And if I do that, the rainbow step wedge problem will be resolved? I don't see how.

3. You said "You can see what the Colormunki wrote in white point XY numbers loading the display profile as RGB Working Space in Photoshop's CustomRGB dialog box in Color Settings and plotting those numbers on a Plankian Locus diagram which should place the coordinates close to the area regarded as 6500K."

Per your instructions I changed the PS working space to the monitor's ICC profile (as shown below), but nowhere does PS show white point XY numbers. I don't follow.

4. Please note that I use the ColorMunki Photo, not ColorMunki Display. So I may not see the same control options that you do. For example, during the calibration setup the ColorMunki Photo instructs me to manually adjust the screen brightness to reach my target of 120cd/m2. But it does not give me hands-on control over the monitor's color temperature. It simply asks me what temperature I want the ColorMunki to adjust the monitor to and it takes it from there. Does your device instruct you to manually dial in (by OSD buttons) the monitor's color temperature to a target of 6500 kelvin?

5. Were you able to fix your rainbow step wedge problem on your Dell and LG? Or are you saying that despite this problem, your prints match your monitor, and so you didn't have a problem per se to fix?

Colormunki Display also asks to adjust for target Brightness, mine is at 100cd/m2. I have a selection for Native white point. see screengrab below.

I noticed you have ADC selected in Colormunki prefs so I'm wondering if your Dell uses internal hardware LUTs, but then the vcgt tags should've shown a flat line. Just for testing I'ld turn ADC off and that ambient stuff off. Keep it simple.

Also have you checked to see if Windows is loading the video card LUTs upon startup. There's been issues in the past on this but I'm not familiar with current Windows or Mac OS in this regard.

The native white point selection in Colormunki is useless if you can't access the OSD RGB gains. Or you could choose native and accept the look of your current neutral white point. You should just do it this way just to check if it fixes the off color step wedge.

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I tried changing the PS working space to the monitor's ICC profile (as shown below), but nowhere does PS show white point XY numbers. I don't follow.

Sorry for not being specific. Once you have your Dell profile as RGB working space click the menu again, hold and scroll up to CustomRGB... A dialog box will show up indicating white point XY numbers as measured by the Colormunki colormeter and written into the icc profile.

To rule out adaptation and surrounding light influences check there's no color in the current native state of your Dell by viewing a white screen filling the entire screen at night with the lights off. If you can't see any color tint, then your safe to set it to native in Colormunki. The colormeter will see native white as one specific tint that you will never see but the profling software will build RGB video card LUT curves and tweak each one to scale that neutral white tint throughout the rest of the gray tones all the way to black.

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Right now I only have two control buttons on the Dell 3007: one for brightness control and the other to power on/off. Should I install this OSD software here and manually adjust the whiteness of the display to match what my eye thinks neutral white looks like? And if I do that, the rainbow step wedge problem will be resolved? I don't see how.

You don't need to see how. Just remake the icc profile with target brightness, native white point, version 2 profile, and turn everything else off - ADC, ambient and whatever else. Don't even mess with the Dell software. It's a process of elimination so start out with the least options.

If that doesn't work reduce Brightness to read at 100cd/m2.

If that doesn't work then install and use the Dell OSD software and try that route.

If that doesn't work, use the Colormunki to profile another display using the simple native settings.

Textshooter. I notice that in your screenshot of Photoshop Colour Settings dialogue you have RGB Working Space set to the monitor profile. You need to select a working colour space such as sRGB, Adobe RGB or ProPhoto RGB. Trying to edit in a non-linear space like that from a monitor will give you no end of problems. I donít know whether this is affecting your display problems.

I use a ColorMunki Photo on a Mac. I set the white point to be D65, not the native point of the display. I do not use LUT to set the luminance of the display neither do I use ADC. It may be that your Windows PC does things differently but I can vouch for the fact that these settings produce good results on an iMac.

Textshooter. I notice that in your screenshot of Photoshop Colour Settings dialogue you have RGB Working Space set to the monitor profile. You need to select a working colour space such as sRGB, Adobe RGB or ProPhoto RGB. Trying to edit in a non-linear space like that from a monitor will give you no end of problems. I donít know whether this is affecting your display problems.

I use a ColorMunki Photo on a Mac. I set the white point to be D65, not the native point of the display. I do not use LUT to set the luminance of the display neither do I use ADC. It may be that your Windows PC does things differently but I can vouch for the fact that these settings produce good results on an iMac.

The OP has his RGB working space set to his monitor display profile because I told him to for temporary reasons in order to scroll up to CustomRGB... to see the white point XY numbers Colormunki measured on his display.

He knows not to set his RGB working space to his monitor space.

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I do not use LUT to set the luminance of the display neither do I use ADC.

Good catch. I forgot to tell him to not use LUTs to adjust Brightness. Plumb forgot about that little piece of crap adjustment.

Thank you for the tips. I will experiment with the settings and see what happens. I've been using this Dell monitor for years and never noticed color casts in my light grays when editing or viewing photos. This issue I'm now having only arose after I learned how to build step wedges in PS last week. Ignorance is bliss.

I noticed you have ADC selected in Colormunki prefs so I'm wondering if your Dell uses internal hardware LUTs, but then the vcgt tags should've shown a flat line.

ADC was disabled, Luminance by Video LUT was disabled, profile version 4 was selected, and 2.2 tone curve was selected when I made the first ICC profile (reply #6 attachment), the one you downloaded and tested. My second ICC profile (reply #10 attachment) had ADC enabled, Luminance by LUT enabled, profile version 2 selected, and 2.2 tone curve selected,

Also have you checked to see if Windows is loading the video card LUTs upon startup?

I did not. How do I check this? The Dell ICC profile appears in the PS color settings> Working Space>RGB> drop down list. If I remember right, the appearance of the monitor's ICC (the one by ColorMunki) in that drop down list means that Windows successfully launched it at startup. Is that what you mean by "Windows loading the video card LUTs upon startup"?

.....I did not. How do I check this? The Dell ICC profile appears in the PS color settings> Working Space>RGB> drop down list. If I remember right, the appearance of the monitor's ICC (the one by ColorMunki) in that drop down list means that Windows successfully launched it at startup. Is that what you mean by "Windows loading the video card LUTs upon startup"?

You can check if your display is using your monitor profile in Color Management (either via Control Panel or typing Color management in search bar)

Your monitor should be identified as shown in first line, check box ticked and the name of current profile should show as default. Should look similar to the attached (you can pretty much ignore the bottom image settings and leave as default)

The OP has his RGB working space set to his monitor display profile because I told him to for temporary reasons in order to scroll up to CustomRGB... to see the white point XY numbers Colormunki measured on his display.

He knows not to set his RGB working space to his monitor space.

Tim is correct. I did that only to find the XY white point numbers. I do it also to verify that Windows launched the correct monitor ICC profile at start up and to confirm that PS sees it, but I don't select it there. Except for bundled Microsoft apps (such as Windows Photo Viewer), Windows 7 relies on third-party apps lik PS to properly utilize the monitor's default ICC profile. I believe Windows just parks the default ICC somewhere the app can easily access it, but don't quote me on that.